~ 11 ~  American Journal of Essential Oils and Natural Products 2015; 3(2): 11-14 ISSN: 2321-9114 AJEONP 2015; 3(2): 11-14 © 2015 AkiNik Publications Received: 02-07-2015 Accepted: 05-08-2015 Prabodh Satyal Department of Chemistry, University of Alabama in Huntsville, Huntsville, AL 35899, USA Prajwal Paudel Department of Chemistry, University of Alabama in Huntsville, Huntsville, AL 35899, USA Bimala Lamichhane Central Department of Chemistry, Tribhuwan University Kirtipur, Kathmandu, Nepal William N. Setzer Department of Chemistry, University of Alabama in Huntsville, Huntsville, AL 35899, USA Correspondence: William N. Setzer Department of Chemistry, University of Alabama in Huntsville, Huntsville, AL 35899, USA Leaf essential oil composition and bioactivity of Psidium guajava from Kathmandu, Nepal Prabodh Satyal, Prajwal Paudel, Bimala Lamichhane, William N. Setzer Abstract The essential oil from the leaves of Psidium guajava, collected from Kathmandu, Nepal, was obtained by hydrodistillation and analyzed by GC-MS. A total of 53 compounds were identified, accounting for 100% of the oil composition. The major components of the essential oil were (E)-nerolidol (35.6%) and (E)-caryophyllene (15.8%), with lower concentrations of (2Z,6E)-farnesol (6.7%), and ledol (5.5%). A cluster analysis of the major components of P. guajava leaf oils has revealed at least nine chemotypes; the sample from Nepal belongs to the nerolidol/caryophyllene chemotype. P. guajava leaf oil showed notable larvicidal activity against Chaoborus plumicornis, marginal nematicidal (Caenorhabditis elegans) and insecticidal (Drosophila melanogaster) activities, and showed no antimicrobial or cytotoxic activity. Keywords: Psidium guajava, essential oil composition, (E)-nerolidol, (E)-caryophyllene, Nepal, chemotype, larvicidal. 1. Introduction Psidium guajava L. (Myrtaceae) is native to Central and South America as well as the Caribbean [1] . P. guajava is known for its plethora of medicinal and therapeutic effects [1-3] . The leaves of this plant are used in traditional medicine for gastroenteritis, dysentery, and diarrhea, and leaf extracts have also been reported to show biological activities including antidiarrheal, antimicrobial, antioxidant, hepatoprotective, anti-allergy, antiplasmodial, antispasmodic, antidiabetic, anti-inflammatory, antinociceptive, and antitussive activities [1-3] . There have been several reports on the leaf oil compositions of P. guajava from various locations around the world, and there is wide variation in the compositions [4] . In this work, we present the leaf oil composition of P. guajava from Kathmandu, Nepal, and compare the composition with several previous analyses. 2. Materials and Methods 2.1 Plant Material The leaves of Psidium guajava were collected from city of Kathmandu, (27° 42′ 0″ N, 85° 20′ 0″ E, 1305 m above sea level) in Kathmandu district in Bagmati Zone of Nepal on 16 May 2011. The plant was identified by Nawal Shrestha, and a voucher specimen has been deposited in the herbarium of the Tribhuwan University, Central Department of Botany, Kirtipur, Nepal. The air-dried sample (85 g) was crushed and hydrodistilled using a Clevenger type apparatus for 4 h to give a clear, colorless essential oil, which was stored at 4ºC until analysis. 2.2 Gas Chromatographic – Mass Spectral Analysis The essential oil of Psidium guajava was analyzed by GC-MS using an Agilent 6890 GC with Agilent 5973 mass selective detector [MSD, operated in the EI mode (electron energy = 70 eV), scan range = 45-400 amu, and scan rate = 3.99 scans/sec], and an Agilent ChemStation data system. The GC column was an HP-5ms fused silica capillary with a (5% phenyl)- polymethylsiloxane stationary phase, film thickness of 0.25 μm, a length of 30 m, and an internal diameter of 0.25 mm. The carrier gas was helium with a column head pressure of 48.7 kPa and a flow rate of 1.0 mL/min. Injector temperature was 200 °C and detector temperature was 280 °C. The GC oven temperature program was used as follows: 40 °C initial temperature, hold for 10 min; increased at 3 °C/min to 200 °C; increased 2°/min to 220 °C. A 1% w/v solution of the sample in CH2 Cl 2 was prepared and 1 μL was injected using a splitless injection technique.